West Nile Virus is a potentially fatal virus. It is in the flaviviridae family; its genus is flavivirus (4). It was originally found only in tropical climates (it is common in Africa, West Asia, and the Middle East) (1), but it spread to temperate areas; it was first detected in the Western hemisphere in 1999 (2). It has since then been found in all 48 of the continental United States (1). Experts believe that it flares up in the summer and then continues through the fall (3). Though it can sometimes be fatal, this is rare. The risk of contracting West Nile Virus is low, and less than 1% who develop it become seriously ill (2). West Nile Virus mainly affects birds, but also sometimes affects humans, horses, dogs, cats, bats, chipmunks, skunks, squirrels, and domestic rabbits (4).
Symptoms:
Mild cases are more common; 20% of people have symptoms which may include: fever, headache, body aches, nausea, vomiting, swollen lymph glands, and a skin rash on the chest, stomach, or back. Mild symptoms may only last a few days.
Less common are severe cases (about 1 in 150 people infected with WNV develop serious cases) and the more severe symptoms may include: high fever, headache, neck stiffness, stupor, disorientation, coma, tremors, convulsions, muscle weakness, vision loss, numbness, and paralysis. These symptoms may last a bit longer, up to a few weeks. Severe cases may include inflammation of the brain, and neurological effects may be permanent. Most commonly, though, people infected with WNV will have no symptoms at all. This is about 80% or 4 out of 5 people (3).
Statistics:
Research from the CDC (Centers for Disease Control and Prevention) says that over 15,000 people in the United States have tested positive for West Nile Virus since it first appeared in 1999, and possibly even more (people with mild or no symptoms). Fatal cases are rare (only about 3.4%); there have only been about 500 deaths (2).
This map shows where cases of WNV have occurred in 2009.
The pink areas are where people have been diagnosed with it.
How does WNV spread?
The most common, and well-known, way that WNV spreads is by infected mosquitoes (3). Mosquitoes are actually infected by biting infected birds (most commonly in the U.S, crows and jays). Then, if the infected mosquito bites a person, it will then transfer to them (1). It usually takes from 3 to 14 days from the bite for a person to get sick . Less common ways are by blood transfusions, organ transplants, and from a mother to an unborn child. These are very rare, however. West Nile Virus can not be spread through touching uninfected people (3).
Treatment?
Unfortunately, there is no specific treatment for West Nile Virus. For mild cases, the symptoms, if there are any, usually subside on their own. However, in severe cases, hospitalization may be necessary. People who are hospitalized receive intravenous fluids, help with breathing, and nursing care (3).
Risk factors:
People over 50 and people with weakened immune systems are more susceptible to contract WNV (1). Safety measures include using bug spray with DEET, wearing clothes that cover all your skin, or just staying inside altogether (4). Also, people who live in areas where mosquito-borne viruses are common are more likely to get bitten by an infected mosquito (1).
Works Cited
"West Nile Virus." Mayo Clinic. Mayo Foundation for Medical Education and
Research, 23 June 2009. Web. 13 Dec. 2009. <http://mayoclinic.com/health/
west-nile-virus/DS00438>.
"West Nile Virus." National Biological Information Infrastructure. U.S.
Geological Survey's Biological Informatics Office, n.d. Web. 13 Dec. 2009.
<http://westnilevirus.nbii.gov/>.
"West Nile Virus: What You Need To Know." Centers for Disease Control and Prevention. N.p., 5 Dec. 2009. Web. 6 Dec. 2009. <http://www.cdc.gov/
ncidod/dvbid/westnile/wnv_factsheet.htm>.
Wikipedia Contributors. "West Nile Virus." Wikipedia. Wikipedia, the Free
Encyclopedia, 13 Dec. 2009. Web. 13 Dec. 2009. <http://en.wikipedia.org/
w/index.php?title=West_Nile_virus&oldid=331472101>.
West Nile Virus
Description:
West Nile Virus is a potentially fatal virus. It is in the flaviviridae family; its genus is flavivirus (4). It was originally found only in tropical climates (it is common in Africa, West Asia, and the Middle East) (1), but it spread to temperate areas; it was first detected in the Western hemisphere in 1999 (2). It has since then been found in all 48 of the continental United States (1). Experts believe that it flares up in the summer and then continues through the fall (3). Though it can sometimes be fatal, this is rare. The risk of contracting West Nile Virus is low, and less than 1% who develop it become seriously ill (2). West Nile Virus mainly affects birds, but also sometimes affects humans, horses, dogs, cats, bats, chipmunks, skunks, squirrels, and domestic rabbits (4).
Symptoms:
Mild cases are more common; 20% of people have symptoms which may include: fever, headache, body aches, nausea, vomiting, swollen lymph glands, and a skin rash on the chest, stomach, or back. Mild symptoms may only last a few days.
Less common are severe cases (about 1 in 150 people infected with WNV develop serious cases) and the more severe symptoms may include: high fever, headache, neck stiffness, stupor, disorientation, coma, tremors, convulsions, muscle weakness, vision loss, numbness, and paralysis. These symptoms may last a bit longer, up to a few weeks. Severe cases may include inflammation of the brain, and neurological effects may be permanent. Most commonly, though, people infected with WNV will have no symptoms at all. This is about 80% or 4 out of 5 people (3).
Statistics:
Research from the CDC (Centers for Disease Control and Prevention) says that over 15,000 people in the United States have tested positive for West Nile Virus since it first appeared in 1999, and possibly even more (people with mild or no symptoms). Fatal cases are rare (only about 3.4%); there have only been about 500 deaths (2).
The pink areas are where people have been diagnosed with it.
How does WNV spread?
The most common, and well-known, way that WNV spreads is by infected mosquitoes (3). Mosquitoes are actually infected by biting infected birds (most commonly in the U.S, crows and jays). Then, if the infected mosquito bites a person, it will then transfer to them (1). It usually takes from 3 to 14 days from the bite for a person to get sick . Less common ways are by blood transfusions, organ transplants, and from a mother to an unborn child. These are very rare, however. West Nile Virus can not be spread through touching uninfected people (3).
Treatment?
Unfortunately, there is no specific treatment for West Nile Virus. For mild cases, the symptoms, if there are any, usually subside on their own. However, in severe cases, hospitalization may be necessary. People who are hospitalized receive intravenous fluids, help with breathing, and nursing care (3).
Risk factors:
People over 50 and people with weakened immune systems are more susceptible to contract WNV (1). Safety measures include using bug spray with DEET, wearing clothes that cover all your skin, or just staying inside altogether (4). Also, people who live in areas where mosquito-borne viruses are common are more likely to get bitten by an infected mosquito (1).
Works Cited
Research, 23 June 2009. Web. 13 Dec. 2009. <http://mayoclinic.com/health/
west-nile-virus/DS00438>.
Geological Survey's Biological Informatics Office, n.d. Web. 13 Dec. 2009.
<http://westnilevirus.nbii.gov/>.
Prevention. N.p., 5 Dec. 2009. Web. 6 Dec. 2009. <http://www.cdc.gov/
ncidod/dvbid/westnile/wnv_factsheet.htm>.
Encyclopedia, 13 Dec. 2009. Web. 13 Dec. 2009. <http://en.wikipedia.org/
w/index.php?title=West_Nile_virus&oldid=331472101>.